1. Field of the Invention
The present invention relates to forming, molding, tipping and welding plastic tubing and, more particularly, to molds having data incorporated in a circuit for controlling the operation of an RF generator to heat, form, mold, tip and weld the tubing within the mold and including a multiplexing capability for interconnecting a plurality of such molds with a single RF generator and controller or computer.
2. Description of Related Prior Art
Molds forming, molding, tipping and welding plastic tubing are connected to a source for producing an electrical signal to heat the mold and thereby cause the forming, molding, tipping or welding of plastic material, such as tubing. Heating of the mold may be by resistance heating or inductive heating as the most common forms. In the latter case, radio frequency (RF) energy is employed and an RF generator is electrically connected to the mold to provide the requisite energy source. For different molds or molds having differing capabilities and functions, the electrical signal applied must be tailored or otherwise adapted within the RF generator to ensure proper and successful forming, molding, tipping and/or welding of the tubing. This procedure has the possibility of inadvertently resulting in operator error. That is, an operator may inadvertently enter incorrect parameters into the control circuit for the RF generator. As a result, the forming, welding, tipping or welding of the plastic tubing will not occur as intended. Sometimes, presumably identical molds are in fact not identical due to manufacturing errors or operator fault. In either case, the parameters preset in the RF generator will not produce the desired function on the plastic tubing.
Presently, each mold requires its own RF generator which results in various less than preferred situations. The use of a single mold with a single RF generator requires an operator between each operation to load the mold with the plastic tubing and after the operation to unload the tubing from the mold. Where a rapid throughput is required or strongly preferred, the time involved for such loading and unloading between each operation has a negative impact on the throughput. The use of a single RF generator to energize a single mold requires significant capital expense when a plurality of molds are required by production criteria. That is, the costs of the mold and the RF generator are significant and result in a significant cost per operation of forming, molding, tipping and/or welding the tubing.
In summary, the current practice is to manually enter the settings into a control module, such as a computer, at the time of installation of the tooling/mold or enter settings in advance and select the appropriate settings at the time of use. In most controlled manufacturing plants, different individuals originate and validate the proper settings for a given operation on a mold than the personnel who use the mold routinely in production. The correct use requires production personnel to duplicate the setting procedure. This takes time and is a potential source of error. Accordingly, a method that would save time and ensure accuracy of the settings is sought.